It is well known to inoculate poultry against contagious diseases such as chicken pox, laryngo-tracheitis, Newcastle disease, etc.
For example, one method of inoculating poultry is to dip a needle or a knife into a bottle of serum in an open crock or other holder and then to "stick" the coated needle into the bird. A portion of the serum frequently drops off from the penetrating instrument and in time this amounts to a substantial loss of serum. In addition, this method provides no accurate measurement of the amount of serum introduced into the bird. The needles or knives are not wiped off between inoculation of birds and, it is almost impossible for a single operator to inoculate a bird himself. At least one hand is needed to hold the bird, and it is difficult for the inoculating party to hold the bird with one hand and to dip the needle or pen knife into the bowl of serum with the other hand while trying to hold the bird. There is also a possibility of the moving bird knocking over the container, losing valuable serum.
In order to inoculate the bird properly, the inoculating party must be seated and, therefore, to achieve efficient inoculation, one sitting party is needed to inoculate the birds and another party is needed to catch the birds and hand them to him, thereby increasing the cost of inoculation.
In response to the above-noted difficulties in inoculating poultry, the inoculators disclosed in U.S. Pat. No. 2,512,882 to Truesdale and U.S. Pat. No. 2,617,918 to Del Pico were conceived.
The Truesdale inoculator comprises a reservoir for the serum. A reciprocable needle extends through the reservoir along its axis. The needle has a pointed end adapted to be projected into the bird to be inoculated. The needle is solid except for an indentation that carries a predetermined dose of serum. Means for reciprocating the needle are provided so that as the indentation enters the reservoir on one stroke, it is charged with the serum, and on the other stroke is pushed out of the reservoir into an inoculating position.
The Truesdale inoculator described above advanced the art of poultry inoculation as it was possible for inoculation of a bird to be accomplished by a single individual working alone. In addition, the serum was contained in a closed reservoir which eliminated the possibility of spillage and furthermore, a precise dose was delivered to the bird. While the Truesdale inoculator was truly an advancement in the art, and is still widely in use today, it too has its deficiencies.
In the poultry industry, when a bird is properly inoculated and resistance to the disease inoculated against develops, this is referred to as a "take". About twenty percent of the time, using the Truesdale inoculator an air lock develops and serum fails to be transferred from the reservoir to the indentation in the needle. Consequently only about 80 percent of the birds inoculated receive a "take" and while this is a vast improvement over the prior art, the percentages could still be improved
It is, therefore, an object of the present invention to provide a poultry inoculator which improves the "take" without sacrificing any of the other advantages found in the Truesdale inoculator.
It is another object of the present invention to provide a poultry inoculator which will reliably deliver a predetermined amount of serum to the bird
It is still further object of the present invention to provide a poultry inoculator which will prevent the serum from coming into contact with the operator.
It is yet another object of the present invention to provide a poultry inoculator which prevents the serum from becoming contaminated with air, dust and dirt, thus maintaining its strength.